SEATTLE URBAN SITE, WASHINGTON

NCDC 1961-1990 Monthly Normals

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Mean Max. Temperature (F) 46.1 50.6 53.7 58.1 64.2 69.6 74.1 74.1 68.8 60.0 51.5 46.2 59.8
Highest Mean Max. Temperature (F) 51.7 56.1 58.3 63.0 68.6 73.3 80.5 80.9 75.0 64.1 54.6 50.0 62.2
Year Highest Occurred 1961 1968 1981 1987 1969 1961 1985 1967 1974 1987 1987 1966 1987
Lowest Mean Max. Temperature (F) 36.9 43.7 48.5 53.7 58.3 64.6 70.4 69.1 64.7 57.1 42.1 40.9 57.7
Year Lowest Occurred 1969 1989 1971 1972 1962 1971 1963 1976 1978 1970 1985 1990 1964
Mean Temperature (F) 41.3 44.3 46.6 50.4 56.1 61.4 65.3 65.7 60.8 53.5 46.3 41.6 52.8
Highest Mean Temperature (F) 46.0 48.8 50.4 54.6 59.3 64.9 69.5 69.9 64.9 56.4 49.7 46.1 54.6
Year Highest Occurred 1983 1963 1986 1987 1987 1969 1985 1967 1967 1965 1965 1966 1987
Lowest Mean Temperature (F) 33.6 36.6 42.4 46.5 52.6 57.9 63.1 62.4 57.2 51.0 37.4 36.3 51.3
Year Lowest Occurred 1969 1989 1971 1972 1962 1971 1986 1973 1972 1970 1985 1990 1985
Mean Min. Temperature (F) 36.4 38.0 39.5 42.7 47.9 53.2 56.4 57.2 52.9 46.9 41.0 37.0 45.8
Highest Mean Min. Temperature (F) 40.5 41.7 42.8 46.2 51.0 57.1 58.8 59.6 56.3 50.6 45.1 42.1 47.1
Year Highest Occurred 1983 1963 1983 1987 1987 1969 1990 1981 1963 1988 1965 1966 1986
Lowest Mean Min. Temperature (F) 30.3 29.5 36.3 39.3 45.1 50.7 54.8 54.3 49.2 43.9 32.6 31.7 43.8
Year Lowest Occurred 1979 1989 1971 1972 1964 1962 1977 1973 1972 1972 1985 1990 1985
Mean Precipitation (in.) 5.35 4.03 3.77 2.51 1.84 1.59 0.85 1.22 1.94 3.25 5.65 6.00 38.00
Highest Precipitation (in.) 10.38 8.09 6.94 4.44 4.24 3.45 2.16 5.49 5.90 8.04 11.20 10.29 50.03
Year Highest Occurred 1986 1961 1971 1972 1977 1964 1978 1977 1969 1975 1983 1979 1968
Lowest Precipitation (in.) 0.60 0.78 0.59 0.91 0.45 0.12 0.11 0.04 0.03 0.29 0.50 1.22 27.78
Year Lowest Occurred 1985 1988 1965 1983 1967 1987 1975 1967 1990 1987 1976 1985 1976
Heating Degree Days (F) 735. 580. 570. 438. 276. 123. 44. 58. 144. 357. 561. 725. 4611.
Cooling Degree Days (F) 0. 0. 0. 0. 0. 15. 54. 80. 18. 0. 0. 0. 167.

Western Regional Climate Center, wrcc@dri.edu